NeuroDAC: an open-source arbitrary biosignal waveform generator.

Objective.Researchers are developing biomedical devices with embedded closed-loop algorithms for providing advanced adaptive therapies. As these devices become more capable and algorithms become more complex, tasked with integrating and interpreting multi-channel, multi-modal electrophysiological signals, there is a need for flexible bench-top testing and prototyping. We present a methodology for leveraging off-the-shelf audio equipment to construct a biosignal waveform generator capable of streaming pre-recorded biosignals from a host computer. By re-playing known, well-characterized, but physiologically relevant real-world biosignals into a device under test, researchers can evaluate their systems without the need for expensivein vivoexperiments.Approach.An open-source design based on the proposed methodology is described and validated, the NeuroDAC. NeuroDAC allows for 8 independent channels of biosignal playback using a simple, custom designed attenuation and buffering circuit. Applications can communicate with the device over a USB interface using standard audio drivers. On-board analog amplitude adjustment is used to maximize the dynamic range for a given signal and can be independently tuned for each channel.Main results.Low noise component selection yields a no-signal noise floor of just 5.35 ± 0.063. NeuroDAC's frequency response is characterized with a high pass -3 dB rolloff at 0.57 Hz, and is capable of accurately reproducing a wide assortment of biosignals ranging from EMG, EEG, and ECG to extracellularly recorded neural activity. We also present an application example using the device to test embedded algorithms on a closed-loop neural modulation device, the Medtronic RC+S.Significance.By making the design of NeuroDAC open-source we aim to present an accessible tool for rapidly prototyping new biomedical devices and algorithms than can be easily modified based on individual testing needs.ClinicalTrials.gov Identifiers: NCT04281134, NCT03437928, NCT03582891.

Ketamine for rapid reduction of suicidal ideation: a randomized controlled trial.

BACKGROUND: Suicide is a devastating public health problem and very few biological treatments have been found to be effective for quickly reducing the intensity of suicidal ideation (SI). We have previously shown that a single dose of ketamine, a glutamate N-methyl-d-aspartate (NMDA) receptor antagonist, is associated with a rapid reduction in depressive symptom severity and SI in patients with treatment-resistant depression. METHOD: We conducted a randomized, controlled trial of ketamine in patients with mood and anxiety spectrum disorders who presented with clinically significant SI (n = 24). Patients received a single infusion of ketamine or midazolam (as an active placebo) in addition to standard of care. SI measured using the Beck Scale for Suicidal Ideation (BSI) 24 h post-treatment represented the primary outcome. Secondary outcomes included the Montgomery-Asberg Depression Rating Scale--Suicidal Ideation (MADRS-SI) score at 24 h and additional measures beyond the 24-h time-point. RESULTS: The intervention was well tolerated and no dropouts occurred during the primary 7-day assessment period. BSI score was not different between the treatment groups at 24 h (p = 0.32); however, a significant difference emerged at 48 h (p = 0.047). MADRS-SI score was lower in the ketamine group compared to midazolam group at 24 h (p = 0.05). The treatment effect was no longer significant at the end of the 7-day assessment period. CONCLUSIONS: The current findings provide initial support for the safety and tolerability of ketamine as an intervention for SI in patients who are at elevated risk for suicidal behavior. Larger, well-powered studies are warranted.

Rebound symptoms following battery depletion in the NIH OCD DBS cohort: clinical and reimbursement issues.

OBJECTIVE: Deep brain stimulation (DBS) is a promising treatment for medication refractory obsessive compulsive disorder (OCD); however, there may be neuropsychiatric symptoms from unintended battery failure. BACKGROUND: Previous studies indicated rebound symptoms from impulse generator (IPG) failure in Parkinson's disease, dystonia, and essential tremor. Unique to OCD is that battery failure may precipitate neuropsychiatric symptoms rather than motor symptoms. METHODS: Six patients with medication refractory OCD received implants as part of the previously reported National Institutional Health (NIH) DBS cohort. All available clinical data and adverse event data was reviewed. RESULTS: The average age of cohort was 42.2 years (30-59 years), and the average baseline Y-BOCS score was 33.8 (31-38). All six subjects were observed to have increased OCD symptomatology during IPG failure; however, Y-BOCS scores remained less than pretreatment range, in five subjects. One of the subjects had a Y-BOCS score greater than pretreatment during the period of IPG failure. In addition, Y-BOCS scores improved back to baseline after IPG replacement in five subjects. Other symptoms potentially related to battery failure included: suicidality (n = 1), mood disturbance (n = 2), panic attacks (n = 1), fatigue (n = 2), and a restless sensation in the arms and legs (n = 1). A small number of subjects reported no side effects associated with IPG failure because of preemptive replacement (n = 2). CONCLUSIONS: This is a preliminary case series detailing the side effects resulting from IPG failure during OCD DBS. Preemptive battery replacement was an effective strategy for avoiding these issues, and timeliness in insurance reimbursement may be considered in the future. Additionally the use of rechargeable batteries may also help this issue. CLINICAL TRIAL REGISTRATION NUMBER: NCT00057603.

Deep brain stimulation of the ventral internal capsule/ventral striatum for obsessive-compulsive disorder: worldwide experience.

Psychiatric neurosurgery teams in the United States and Europe have studied deep brain stimulation (DBS) of the ventral anterior limb of the internal capsule and adjacent ventral striatum (VC/VS) for severe and highly treatment-resistant obsessive-compulsive disorder. Four groups have collaborated most closely, in small-scale studies, over the past 8 years. First to begin was Leuven/Antwerp, followed by Butler Hospital/Brown Medical School, the Cleveland Clinic and most recently the University of Florida. These centers used comparable patient selection criteria and surgical targeting. Targeting, but not selection, evolved during this period. Here, we present combined long-term results of those studies, which reveal clinically significant symptom reductions and functional improvement in about two-thirds of patients. DBS was well tolerated overall and adverse effects were overwhelmingly transient. Results generally improved for patients implanted more recently, suggesting a 'learning curve' both within and across centers. This is well known from the development of DBS for movement disorders. The main factor accounting for these gains appears to be the refinement of the implantation site. Initially, an anterior-posterior location based on anterior capsulotomy lesions was used. In an attempt to improve results, more posterior sites were investigated resulting in the current target, at the junction of the anterior capsule, anterior commissure and posterior ventral striatum. Clinical results suggest that neural networks relevant to therapeutic improvement might be modulated more effectively at a more posterior target. Taken together, these data show that the procedure can be successfully implemented by dedicated interdisciplinary teams, and support its therapeutic promise.

Symptom dimensions and cognitive-behavioural therapy outcome for pediatric obsessive-compulsive disorder.

OBJECTIVE: To examine whether obsessive-compulsive disorder (OCD) symptom subtypes are associated with response rates to cognitive-behavioural therapy (CBT) among pediatric patients. METHOD: Ninety-two children and adolescents with OCD (range = 7-19 years) received 14 sessions of weekly or intensive (daily psychotherapy sessions) family-based CBT. Assessments were conducted at baseline and post-treatment. Primary outcomes included scores on the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS), remission status, and ratings on the Clinical Global Improvement (CGI) and Clinical Global Impression - Severity (CGI-Severity) scales. RESULTS: Seventy-six per cent of study participants (n = 70) were classified as treatment responders. Patients with aggressive/checking symptoms at baseline showed a trend (P = 0.06) toward improved treatment response and exhibited greater pre/post-treatment CGI-Severity change than those who endorsed only non-aggressive/checking symptoms. Step-wise linear regression analysis indicated higher scores on the aggressive/checking dimension were predictive of treatment-related change in the CGI-Severity index. Regression analysis with CY-BOCS score as the dependent variable showed no difference between OCD subtypes. CONCLUSION: Response to CBT in pediatric OCD patients does not differ substantially across subtypes.

Panic and fear induced by deep brain stimulation.

BACKGROUND: Mood, cognitive, and behavioural changes have been reported with deep brain stimulation (DBS) in the thalamus, globus pallidus interna, and anterior limb of the internal capsule/nucleus accumbens region. OBJECTIVE: To investigate panic and fear resulting from DBS. METHODS: Intraoperative DBS in the region of the right and then left anterior limb of the internal capsule and nucleus accumbens region was undertaken to treat a 52 year old man with treatment refractory obsessive-compulsive disorder (OCD). Mood, anxiety, OCD, alertness, heart rate, and subjective feelings were recorded during intraoperative test stimulation and at follow up programming sessions. RESULTS: DBS at the distal (0) contact (cathode 0-, anode 2+, pulse width 210 ms, rate 135 Hz, at 6 volts) elicited a panic attack (only seen at the (0) contact). The patient felt flushed, hot, fearful, and described himself as having a "panic attack." His heart rate increased from 53 to 111. The effect (present with either device) was witnessed immediately after turning the device on, and abruptly ceased in the off condition CONCLUSIONS: DBS of the anterior limb of the internal capsule and nucleus accumbens region caused severe "panic." This response may result from activation of limbic and autonomic networks.

Disgust and the insula: fMRI responses to pictures of mutilation and contamination.

Although previous functional brain imaging studies have found that the insula responds selectively to facial expressions of disgust, it remains unclear whether the insula responds selectively to disgust-inducing pictures. In this fMRI study, healthy volunteers viewed pictures of contamination, human mutilation, attacks and neutral scenes during scanning, and then rated pictures for the 'basic' emotions. The anterior insula responded to contamination and mutilation but not attacks, while the ventral visual areas responded to attacks and mutilations more strongly than contamination. The above activations were predicted by disgust and arousal ratings respectively. Additionally, mutilations uniquely activated the right superior parietal cortex. These results support selective disgust processing at the insula, and suggest distinct neural responses to contamination and mutilation.

Progress toward analysis of D8/17 binding to B cells in children with obsessive compulsive disorder and/or chronic tic disorder.

BACKGROUND: Previous research has suggested that a subgroup of children with obsessive compulsive disorder (OCD) have neuropsychiatric sequelae of streptococcal pharyngitis, similar to that seen in the neurological manifestation of rheumatic fever (RF). Monoclonal antibody D8/17 demonstrates increased binding to B cells in patients with RF and in patients with neuropsychiatric disorders using immunofluorescent microscopy. OBJECTIVE: The aim of this study was to determine if an earlier immunofluorescent microscopy study of monoclonal antibody D8/17 in childhood-onset OCD and/or chronic tic disorder (CTD) could be replicated using the more objective method of flow cytometric analysis. METHOD: D8/17 binding to B cells was determined in patients with OCD and or CTD (N=32), and healthy controls (N=12) by flow cytometric analysis. RESULTS: Subjects with OCD/CTD showed increased mean cell binding (26.0%) of monoclonal antibody compared with healthy controls (9.1%) (p<0.001). When using the threshold of greater than 19% binding (95% upper confidence interval) as a measure of positivity, 65.6% of patients compared with 8.3% of controls showed increased antibody binding to B cells (p=0.01). CONCLUSIONS: Although this study reports positive results, many methodological issues will need to be addressed before generalized use of assay for diagnostic purposes.

Obsessive compulsive disorder: is there an association with childhood streptococcal infections and altered immune function?

During the last few years, an increased interest in the possibility of immune mediated pathophysiology of obsessive compulsive disorder (OCD) and related disorders has been seen. In the late 1980s, the National Institute of Mental Health reported an increase of obsessive compulsive symptoms in patients with Sydenham chorea (SC). Subsequently, a precipitating streptococcal infection in children with sudden onset of OCD symptoms but no chorea led to the coining of PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcus). This association has furthered interest in studying immune parameters in non-PANDAS OCD as well. This article will review the neuropsychiatric findings in OCD and Tourette syndrome (TS) with emphasis placed on PANDAS, and its association with SC, and a review of the existing studies that have assessed immunologic measures in patients with OCD and TS.

The psychobiology of obsessive-compulsive disorder: how important is the role of disgust?

Psychobiologic models of obsessive-compulsive disorder (OCD) have focused on cortico-striatal-thalamic-cortical (CTSC) circuits, noting normal function in cognitive and motoric procedural strategies. Such models have relied on the classification of OCD as an anxiety disorder, seldom exploring other relevant emotions. Based on the hypothesis that a central emotion in OCD is disgust, the authors review the literature on its psychobiology and its relevance to current models of OCD. There are important parallels between the psychobiology of OCD and that of disgust. Obsessive- compulsive disorder may be conceptualized in terms of a false contamination alarm in which disgust plays a crucial organizing or embodying role, not only at a basic brain level, but also in terms of the psychosocial aspects of the disorder. Just as psychobiologic models of panic disorder and post- traumatic stress disorder have been strengthened by the inclusion of preclinical work on amygdala-mediated fear conditioning, so findings on disgust and its mediating CSTC circuits may generate useful hypotheses for OCD research.

The cognitive-affective neuroscience of obsessive-compulsive disorder.

There is substantial evidence that obsessive-compulsive disorder (OCD) is mediated by specific cortico-striatal- thalamic-cortical (CTSC) circuits. Here we discuss very recent publications that address the following questions: How does damage to CSTC circuitry come about?; What are the neurochemical systems involved in mediating this circuitry?; and What are the implications of such damage for understanding the pathogenesis and management of OCD? A cognitive-affective neuroscience perspective is helpful in advancing our understanding of the role of these circuits in OCD and the dysfunctional procedural strategies that appear to characterize this disorder. Furthermore, this model is becoming integrated with a range of data including brain imaging, genetic, immunologic, and neurochemical findings.

On defining Sydenham's chorea: where do we draw the line?

Sydenham's chorea (SC) is a major manifestation of rheumatic fever characterized by an array of neuropsychiatric symptoms that vary in severity, timing, and character. Some of the same symptoms are seen in Tourette's syndrome and childhood-onset obsessive-compulsive disorder. Genetic vulnerability appears to play a role in all three conditions. The term PANDAS (pediatric autoimmune neuropsychiatric disorder associated with streptococcus) has been introduced to describe a putative subset of obsessive-compulsive disorder and Tourette's syndrome that bears some resemblance to Sydenham's chorea. This article discusses whether PANDAS should be subsumed under Sydenham's chorea, thus expanding the diagnostic boundaries of Sydenham's chorea to include primarily neuropsychiatric presentations now classified as cases of obsessive-compulsive disorder or Tourette's syndrome. We conclude that PANDAS is a useful construct, but that it would be premature to view it as a subset of Sydenham's chorea-whether defined narrowly or broadly.

Segregation analysis of obsessive-compulsive disorder using symptom-based factor scores.

Obsessive-compulsive disorder (OCD) is a complex psychiatric disorder characterized by recurring obsessions or compulsions that cause significant distress to the patient or significantly interfere with the patient's normal home, work, or social activities [Diagnostic and Statistical Manual of Mental Disorders, 4th Edition. Washington, DC: American Psychiatric Association, 1994]. Twin and family studies have suggested that OCD has a significant genetic component. We performed complex segregation analyses using POINTER with families ascertained through an OCD-affected proband. In an attempt to resolve the phenotypic heterogeneity observed among individuals with OCD these segregation analyses used four factor-analytic symptom dimensions to subset the family sample based upon probands' symptom factor scores. Analysis of the entire sample allowed rejection of only the no transmission model; that model was also rejected in all subsequent analyses. Limiting the analyses to families with at least one OCD-affected member in addition to the proband (the demonstrably familial form of OCD) allowed rejection of all models except the mixed model. Analyses limited to families of high-factor-3 (symmetry and ordering symptoms) probands led to rejection of the polygenic model, indicating the involvement of a major locus. Additionally, the relative risk of OCD or subclinical OCD was 1.7 for relatives of probands with a factor 3 score greater than zero compared with relatives of probands with a low factor score. The symptoms attributed to high factor 3 scores (symmetry and ordering) may constitute a genetically significant symptomatic subtype of OCD. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:669-675, 1999.

Obsessive-compulsive disorder: diagnosis and treatment.

Obsessive-compulsive disorder (OCD) is a chronic, disabling anxiety disorder that is characterized by recurrent obsessions and uncontrolled compulsions such as repetitive behavioral or mental acts that are performed in response to an obsession. OCD often occurs comorbidly with a number of depressive and anxiety disorders. In addition, patients with OCD suffer significant personal and social morbidity and may have difficulty maintaining a job, finishing school, and developing relationships. The backbone of pharmacologic treatment for OCD is a 10- to 12-week trial with a selective serotonin reuptake inhibitor (SSRI) in adequate doses. In most cases, treatment should be initiated with an SSRI because of the superior safety, tolerability, and equivalent efficacy of this class of drugs compared with clomipramine. When dealing with patients who do not respond to one SSRI, effective alternatives include switching to a different SSRI, combining another medication or behavioral therapy with SSRI therapy, considering novel or experimental drug treatments, or employing nonpharmacologic biological approaches, such as electroconvulsive therapy, neurosurgery, or repetitive transcranial magnetic stimulation. This article provides an update on the diagnosis and medical management of OCD and will discuss guidelines for the use of SSRIs and novel approaches for managing treatment-refractory patients.

Effects of left frontal transcranial magnetic stimulation on depressed mood, cognition, and corticomotor threshold.

BACKGROUND: The pathophysiology of depression may include synaptic hypoactivity of left prefrontal cortex. Several groups of investigators have described improved mood associated with rapid transcranial magnetic stimulation (rTMS) but have not looked for possible cognitive side effects associated with left prefrontal magnetic stimulation. METHODS: We measured the effects of left prefrontal rTMS on mood, cognition, and motor evoked potential threshold in 10 patients with medication-resistant major depression. RESULTS: In a 2-week open trial of left prefrontal rTMS off antidepressant medications, scores on the Hamilton Rating Scale for Depression and the Beck Depression Inventory decreased by 41% and 40%, respectively. After resuming pre-rTMS antidepressant medication, improvement in mood was still significant at 1 and 3 months later. rTMS had no adverse effects on neuropsychological performance. rTMS treatments were associated with significant decreases in motor evoked potential threshold in the 9 of 10 patients who remained off psychotropic medications during the 2-week treatment period. CONCLUSIONS: These preliminary data suggest that left prefrontal rTMS is safe and improves mood in patients with medication-resistant major depression. Changes in motor evoked potential threshold suggest that prefrontal rTMS may alter brain activity at sites remote from the stimulation. Double-blind, sham-controlled studies are needed.

Patterns of remission and relapse in obsessive-compulsive disorder: a 2-year prospective study.

OBJECTIVE: This study examined the course of illness in patients with obsessive-compulsive disorder (OCD) over a 2-year period. METHOD: Sixty-six patients with a primary diagnosis of DSM-III-R OCD were followed prospectively for 2 years. Baseline information was collected on demographic characteristics, Axis I and II diagnoses, and severity of OCD symptoms. Follow-up measures obtained at 3, 6, 12, and 24 months after baseline assessment included information on symptomatic and diagnostic status as well as behavioral and somatic treatments received. RESULTS: The probability of full remission from OCD over the 2-year period was 12%. The probability of partial remission was 47%. After achieving remission from OCD, the probability of relapse was 48%. No factors were identified that significantly predicted full or partial remission. Seventy-seven percent (N = 51) of the subjects received a serotonin reuptake inhibitor (SRI) for > or =12 weeks, and 68% (N = 45) received medium-to-high doses of SRIs for > or =12 weeks. Only 18% received a full trial of behavior therapy. CONCLUSION: Despite exposure to at least 1 adequate trial of an SRI, the likelihood of full remission of OCD in this study was low. Results of this study also suggest that behavior therapy may be under-utilized.

Effects of the CCK(B) antagonist CI-988 on responses to mCPP in generalized anxiety disorder.

In order to evaluate the effect of the CCK(B) antagonist CI-988 on behavioral, neuroendocrine, and physiologic responses to the mixed, post-synaptic serotonin (5-HT) agonist/antagonist mCPP, 16 patients with a principal DSM-III-R diagnosis of generalized anxiety disorder (GAD) were enrolled in a study that involved two challenge tests. On one day, patients received a single oral dose of CI-988 followed 30 min later by an i.v. infusion of 0.1 mg/kg mCPP. On a second test day patients received placebo CI-988 followed 30 min later by active i.v. mCPP. The sequence of CI-988 was randomly assigned and the testing was conducted in double-blind fashion. In an initial dose-finding phase (N = 6) with a dose of CI-988 of 25 mg, there were no significant between-test differences in behavioral response to mCPP. Accordingly, the second phase of the study was conducted with a CI-988 dose of 100 mg in another of patients (N = 10). CI-988 (100 mg) was well tolerated and had no significant effects on pretest anticipatory anxiety. There was no significant blunting of the anxiety response to mCPP as a result of CI-988 administration, nor did CI-988 affect physiologic or neuroendocrine measures. Correlations between peak changes in plasma levels of CI-988 and mCPP-induced anxiety in the high-dose patient group were not significant. Overall, these findings did not provide evidence of anxiolytic effects of CI-988 in patients with GAD. The lack of effect of CI-988 on neuroendocrine and physiological measures further suggests that CI-988's pharmacological effects could be independent of 5-HT function. However, follow-up studies using higher doses of CI-988 are indicated to confirm this preliminary finding as are studies more closely evaluating the interrelationship between CCK and 5-HT function in GAD.

Possible role of neuropeptides in obsessive compulsive disorder.

The most consistent finding in clinical research of obsessive compulsive disorder (OCD) is the significant treatment advantage of potent serotonin uptake inhibitors (SUIs) over other classes of antidepressant and antianxiety drugs. Clinical neurobiological studies of OCD, however, have yielded limited and inconsistent evidence for significant fundamental abnormalities in monoamine systems including serotonin, norepinephrine and dopamine. Furthermore, one-third to one-half of OCD patients do not experience a clinically meaningful improvement with SUI treatment. Investigation beyond the monoamine systems may be necessary in order to more fully understand the pathophysiology of obsessive-compulsive symptoms and develop improved treatments. Evidence from preclinical studies suggests that neuropeptides may have important influences on memory acquisition, maintenance and retrieval; grooming, maternal, sexual and aggressive behavior; fixed action patterns; and stereotyped behavior; these phenomena may relate to some features of OCD. In addition, extensive interactions have been identified in the brain between neuropeptidergic and monoaminergic systems, including co-localization among specific populations of neurons. The purpose of this review is to present the current knowledge of the role of neuropeptides in the clinical neurobiology of children, adolescents and adults with OCD focusing primarily on results from pharmacological challenge and cerebrospinal fluid studies. Where evidence exists, developmentally regulated differences in neuropeptide function between children and adolescents versus adults with OCD will be emphasized; these data are intended to underscore the potential importance of establishing the age of symptom onset (childhood versus adult) in individual patients with OCD participating in clinical neurobiological investigations. Likewise, where information is available, differences in measures of neuropeptides between patients with non-tic-related OCD versus tic-related OCD will be highlighted; these data will demonstrate the critical value of diagnostic precision, as these two particular subtypes of OCD may have different neurochemical underpinnings.